Dressing rollers

3M Abrasive Systems Division
We make Profiles
Dressing rollers
for more efficiency,
best results,
and highest precision
english
„
WENDT ™ – A strong brand in a
strong corporate group.
“
As a strong 3M brand, WENDT stands today for highly innovative grinding solutions for
grinding hard-to-grind materials. As an incomparable system developer, we offer precision
grinding machines, laser processing centers, diamond and CBN grinding tools, as well as
dressing tools and dressing machines from a single company.
With our international team of consultants and our regional staff, we maintain an effective
sales and customer service network. We work out your custom system solution in close
cooperation with you as a user.
Regardless of which application, the extraordinary quality of our machines and tools in
combination with the experience and creativity of our specialists guarantees you will receive
the optimal solution for your application problems.
2
Content
Preface 4
Diamond Pattern 6
Tolerances and Variants 8
Selection Criteria and Preparations for Use 10
Work Conditions 12
Form Types / Setting Pattern
14
Sales and Service 16
We love what we do –
Dressing rollers for every application
As an integral part of modern precision grinding technology, diamond dressing rollers are primarily used in medium-sized and mass production.
On the following pages, we present a wide variety of designs of our diamond dressing tools for use in a large number of different areas of
application.
We would be happy to help you with proven recommendations regarding the applications and operating conditions of our diamond profile
dressing rollers and our diamond form dressing rollers.
4
Diamond profile dressing rollers
• To shape grinding wheels in the shortest
possible time
• Profiling of the grinding wheel in only one
operation using the plunge-cut dressing
method
• Extreme accuracy, even with highly complex profile contours
• Highest cost-effectiveness
Vr
Diamond profile roller
frd
Vsd
nr
Grinding wheel
nsd
Diamond form dressing rollers
• P rofiling of the grinding wheel along the
desired contour by moving the diamond
dressing roller
• Extreme accuracy for simple and highly
complex profile contours
• Highest cost-effectiveness
VS
Vfr
VR
Vfa
5
When it‘s really hard –
Diamond Pattern
The arrangement and grain density
of the diamonds on the coated profile
surface or in the bond is what we call the
diamond pattern. On heavily worn parts
of the profile, e.g. on the edges, edge
reinforcements are used, in which case
the setting density is determined by the
mesh size.
A
B
C
D
E
F
Our form dressing rollers are available
with hand-set or randomly distributed
diamond patterns, and are increasingly
being equipped with polycrystalline diamond
inserts that can be reground several times.
Depending on the customer‘s requirements,
the diamond patterns of our dressing tools
are specified after considering the profile
geometry, the required workpiece surface
quality, the precision requirements, and the
work conditions.
Various types of diamonds
A Natural diamond grain, rounded
B Natural diamond grain, sharp
C Synthetic diamond grain
D Natural edge reinforcement, octahedron-shaped
E Natural edge reinforcement, needle-shaped
F Monocrystalline synthetic edge reinforcement
G Polycrystalline diamond inserts
Screen grain sizes
FEPA Standard (metric)
Size range
Screen mesh size (μm)
narrow
wide
D1181
D1182
D1001
D851
D852
D711
D601
D602
D501
D426
D427
D356
D301
D251
D252
D213
D181
D151
6
1180
1000
850
710
600
500
425
355
300
250
212
180
150
- 1000
- 850
- 710
- 600
- 500
- 425
- 355
- 300
- 250
- 212
- 180
- 150
- 125
US Standard ASTM-E-11 (mesh)
Size range
Grains per ct
narrow
wide
16 / 18
18 / 20
20 / 25
20/30
25 / 30
30 / 35
30/40
35 / 40
40 / 45
40/50 45 / 50
50 / 60
60 / 70
60/80
70 / 80
80 / 100
100 / 12
< 100
˜ 200 ˜ 300
˜ 400
˜ 700
˜ 1200
˜ 2000
˜ 4000
˜ 6000
˜ 8000
˜ 17000
˜ 25000 ˜ 50000
G
The following are the determining factors
for the diamond pattern:
The diamond grain size
We determine the diamond grain size according to the profile geometry, the smallest convex
radius present in the profile in connection with the corresponding enclosed angle, and the
required surface quality of the workpiece.
The grain size can only be determined based solely on the required workpiece surface quality
for profile geometries that allow edge reinforcements to be inserted for small radii. In general,
the grain size should be as large as possible in order to extend the lifespan of the tools. The
diamond grain size required is selected from the narrow or wide size range of the FEPA*
standard for diamond grain sizes.
* Federation of the European Producers of Abrasives
The diamond content
The diamond content, which is specified using carats as the unit of weight (1 ct = 0.2 g),
of tools manufactured using electroplating technology depends on the grain size and is
calculated using the area of the surface covered with diamonds and the grain density in ct/
cm2. For tools manufactured using a sintering process, though, the diamond content results
from the coating volume and the concentration (ct/cm3). The number of edge reinforcements
and polycrystalline inserts is calculated from the mesh dimensions. Precise knowledge of
the diamond content, the grain size, the diamond quality, and the edge reinforcement are
especially important when comparing prices.
The diamond quality
We use naturally shaped or rounded natural or synthetic grains in our dressing tools. The base
grains consist of block-like, high-strength crystals with an irregular surface that gives them
outstanding bonding properties and prevents grain pull-out.
Needle-shaped or octahedron-shaped natural diamonds are used for edge reinforcement,
but we also use monocrystalline synthetic diamonds. The latter are also used to
manufacture highly wear-resistant and thermally stable form dressing rollers. The
diamond quality is specified based on the diamond pattern and the processing
conditions while taking the effective roughness the grinding wheel into account.
The following generally applies …
… the denser the diamond pattern, the sharper
the grain, i.e. naturally shaped grains are used for
random diamond patterns and rounded grains are
used for hand-set diamond patterns.
7
Exact, accurate, precise –
Tolerances Our diamond profile dressing rollers and
diamond form dressing rollers are balanced
according to DIN ISO 1940 with a quality grade
of G1.
Type of Design
Designation
IZ
PM
SM
Dimension t
Parallelity
0.002
0.002 0.005
0.005
Concentricity
0.002
0.002 0.005
0.005
Axial run-out
0.002
0.002 0.005
0.005
Run-out
0.004
0.004 0.01
0.02
Cylindrical form
0.004 0.004
(0.002) (0.002)
0.01
0.02
Smoothness
0.004
0.004
0.01
0.02
Line form
0.004
0.01
(0.002) (0.003)
0.01
0.02
Radius
Angle
Length
For pattern setting
designs
8
NZ
Symbol
The tolerances
The manufacturing precision of our diamond
dressing rollers is generally 2/3 of the
workpiece dimensional tolerances and form
tolerances (table to the right). It is possible for
use to manufacture our dressing tools with
very tight tolerances, but the following applies:
the lower the tolerance, the higher the price.
± 0.002 ± 0.004
± 0.025 ± 0.025 R
(± 0.001) (± 0.003)
0.004 0.004
(0.002) (0.002)
0.01
0.01
± 0.002 ± 0.002
± 0.025 ± 0.025
(± 0.001) (± 0.001)
± 0.01
± 0.01 ± 0.025 ± 0.025
Axial length
(± 0.003) (± 0.005)
Radial length
± 0.002 ± 0.01
± 0.05
± 0.05
LA
LR
LAS
LRS
Variants
Reverse plated
• NZ variant (randomly distributed diamonds)
• NS variant (hand-set diamonds)
• NM variant (hand-set/randomly distributed diamonds)
To electroplate these tool variants during the manufacture of the
tools using the reverse plating method, a metal female mold with the
reverse image of the dressing roller is produced first. The diamond
grains are placed on surface of the profile (randomly distributed
for the NZ variant, hand-set for the NS variant, hand-set/randomly
distributed for the NM variant). On all dressing tools manufacture
using the reverse plating method, the diamonds lay on the enveloping
surface of the profile so that each grain actively participates in the
dressing process and enable the longest possible lifespans. Tools of
these types allow even the tightest tolerances to be maintained and
are used as a standard for all types of profiles, and especially for very
fine profiles.
They are also used when a high effective roughness is desired. The
NM variant is used increasingly to grind workpieces that tend to burn
when grinding certain parts of the profile.
Reverse method by infiltration
• IZ variant (randomly distributed diamonds)
• IS variant (hand-set diamonds)
To manufacture these very robust tools made using the reverse
plating by infiltration method, a graphite mold with the reverse
image of the profile of the dressing roller is produced. The shrinkage
inherent in the process needs to be taken into account when making
the mold. The diamond grains are placed on the surface of the profile
(randomly distributed for the IZ variant, hand-set for the IS variant).
These variants allow tight tolerances to be maintained, but there are
some profile-dependent restrictions for the IZ variant, although the
IZ variant has the advantage of shorter manufacturing times. The IS
variant is recommended for profiles with featuring high, narrow ribs
that cannot be electroplated.
Positive electroplated
• PM variant (randomly distributed diamonds)
Tools of this type are manufactured using the positive electroplating
process. A steel hub bears the profile the dressing roller reduced by
an amount equal to the size of the diamond grains. The diamond grit
is then placed on the surface of the hub profile and electroplated with
nickel. The diamond grains are on single plane on the hub. Due to
variations in size of the diamond grains, is the active surface of the
dressing roller is rough and uneven. Tools of this type are therefore
extremely aggressive and have the highest effective roughness.
Dressing rollers manufactured using the positive electroplating
process are not used in applications with high precision requirements
and feature lower manufacturing costs and high efficiency since the
hub can be recoated several times.
Sintered
• SM variant (interspersed with diamonds)
To manufacture these tools using the sintering process, a prefabricated
dressing roller body is mounted in a press mold made of hot work tool
steel. The diamond coating, a mixture of diamond grains and bonder,
is poured into the mold, compacted at high pressure, and sintered at
high temperature.
After cooling, the tool is carefully finished until the final shape
is reached and the diamond grains are exposed. In contrast to all
other variants that have a coating thickness corresponding to the
grain size, a coating thickness of several times the diamond grain
size is possible with this variant. In general, thickness of 2, 3, or
5 mm are used in applications. Dressing rollers of this design are
used for simple profiles without high precision requirements and are
applied so that the original shape is retained for a long time. They are
sharpened occasionally to achieve longer tool lifespans. In the form
of dressing rollers or dressing cups, they are suitable for dressing
ceramic-bonded CBN grinding wheels.
s
t
n
a
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a
V
9
The right tool
for every application –
Selection Criteria
As an orientation aid, we have collected the essential features and characteristics
of our most important types of tools:
Variants
NZNSNM IS IZ PMSM
Manufacturing process
Reverse electroplating
Positive electroplating
Nickel plated
Bond
Infiltrated tungsten
Sintered bronze
Randomly distributed
Hand-set
Hand-set/randomly distributed
Saturated
Diamond pattern
Edge reinforcement
Polycrystalline shape
Grain size
Highest execution accuracies
Finest profiles
Profile with high, narrow ribs
Highly robust
High effective roughness
Partial avoidance of grinding burn
Shortest delivery times
10
≥ D151
≥ D602
e
s
U
r
o
f
s
n
o
i
t
a
r
a
p
e
r
P
Preparations for Use
The installation
The proper installation of a diamond dressing roller has a major influence on the dressing/
grinding results and the lifespan of the dressing tool. We recommend you install the tool
according to the following rules:
• Check for cleanliness and clean all components, if necessary.
• Check to ensure the surfaces of the arbor, the spacer ring, and the clamping nut are
in perfect condition. Pay special attention to any friction deposits or machining marks
present.
•
Check the parts to be mounted to ensure the manufacturing tolerances are
maintained. The actual size of the dressing roller hole can be found in the test report.
The determination and maintenance of the minimum tolerance clearance is especially
important in this regard.
• Test of the concentricity and axial run-out of the grinding wheel arbor. The maximum
permissible run-out error is 0.002 mm.
• Clean the parts to be mounted with a towel soaked in acid-free oil so that a thin film of
oil remains on the parts. Avoid leaving fingerprints on the connection points.
• Push the parts carefully in the specified order, and only by moving them in the axial
direction, onto the arbor.
A
A
A
A
A
A
A
A
A
A
Installation is much easier if the dressing roller is warmed up in an oil or water bath.
The maximum permissible temperature is 40°C. Do not warm the dressing roller under
running water. After installation is completed, conduct a test of the radial and axial runout of the dressing roller on the arbor and again on the corresponding test collar after
installation in the machine. If the values of radial and axial run-out deviation are greater
than 0.005 mm, then the dressing roller must be reinstalled, taking the points stated
into account.
11
We know how to do it –
Work Conditions
The ability to influence process-relevant factors such as the working conditions, configuration of the axes, speed ratio, direction of rotation,
infeed, and rollout when dressing with diamond profile dressing rollers offers numerous opportunities for optimization of the results.
When dressing with form dressing rollers, it is also possible to specifically influence the topography on the grinding wheel and optimize the
results by matching the individual factors such as the working conditions, infeed per overflow, speed ratio, direction of rotation, feed rate, etc.
Examples of influencing factors that can be coordinated:
Direction of rotation
Unidirectional and counterdirectional dressing refers to the relative direction of rotation of
the diamond dressing roller with respect to the grinding wheel. They have correspondingly
different effective roughnesses (Figure 1). Since unidirectional dressing is associated with
high effective roughnesses, it is used for high performance dressing of rough grinding wheels
and fine grinding of critical profiles that have a tendency to burn when grinding. By changing
the speed ratio, it is possible to have a greater influence on the effective roughness than with
counterdirectional dressing. Counterdirectional dressing, which is associated with a lower
effective roughness, is used for fine grinding wheels used to grind non-critical profiles that do
not tend to burn during grinding.
Diamond profile and form dressing rollers
Diagram 1
Diamond profile dressing rollers
Diagram 2
12
fdr = 0.72 µm
fdr = 0.18 µm
Unidirectional
Counterdirectional
15
ad = 0.7 µm
ad = 0.5 µm
10
Recommended working area
Effective roughness Rts [µm]
Effective roughness Rts [µm]
10
8
6
Unidirectional
4
5
2
V
qd = R
VS
0
1.0
0.75
0.5
0.25
0
-0.25
Speed ratio qd
12
-0.5
-0.75
-1.0
Counterdirectional
0
0
80
160
Number of dwell revolutions
240
320
Speed ratio (qd)
The greatest influence on the effective roughness is obtained by changing the speed
ratio qd, which is the quotient of the circumferential speed of the dressing roller VR to
the circumferential speed of the grinding wheel VS (Figure 1: Unidirectional and
counterdirectional dressing at different feed increments). Speed ratios of 1 or almost
1 are not permitted since they indicate that the diamond dressing roller is either
dwelling on the grinding wheel or that the dressing roller is prematurely worn or
damaged.
Terms and Formulas
Vr
rp
Infeed (ad)
Our parameter for the infeed is the radial feed increment ad (μ) of the diamond
dressing roller per revolution of the grinding wheel. As the infeed increases (for
unidirectional dressing more than for counterdirectional dressing), the effective
roughness increases (Figure 1). The recommended feed increments are between
0.25 – 0.5 μ per revolution of the grinding wheel. The total infeed selected should
always be as small as necessary to restore the grinding wheel profile (generally <
0.03 mm). When continuous dressing (CD), the tool is fed continuously at a rate of
up to 0.2 μ per revolution of the grinding wheel. When dressing with diamond form
dressing rollers, the feed increment depends mainly on the type of form dressing
roller, the desired grinding wheel profile, the cutting conditions, and whether you
are rough grinding or finishing grinding. Due to the numerous combinations of the
application and working conditions, we can only specify 0.1–0.5 mm as a standard
value for rough grinding and 0.005–0.05 mm for finishing grinding.
Form roller
Vsd
aed
Axial feed rate (v)
Another working parameter required when using diamond form dressing rollers is
a feed movement with velocities in the axial or tangential direction. As the feed rate
increases (in unidirectional dressing more than in counterdirectional dressing), the
effective roughness increases. Since the feed rate depends on the combination of
the application and working conditions, we can only specify 100–300 mm/min as
a standard value for rough grinding and 30–100 mm/min for finishing grinding.
Dwell revolutions (na)
The effective roughness is also influenced by the number of dwell revolutions (na).
As the number of revolutions increases (for unidirectional dressing more than for
counterdirectional dressing), the effective roughness decreases (Figure 2). At about
150 dwell revolutions for unidirectional dressing and 50 dwell revolutions for
counterdirectional dressing, it becomes impossible to minimize the values any
further. While the number of dwell revolutions needs to be kept low in cases where
there is a tendency of grinding burn, they should be increased when the surface
roughness values of the workpiece are high. (All values were determined in fixed
systems with specific machine and equipment stiffness values, but are still useful
in a general sense.)
Vr
Vfad
apd
fad
Grinding wheel
bd
Dressing overlap ratio
Dressing speed ratio
apd
Ud = ––
fad
with bd = √ 8·rp · aed
vr
qd = ± ––
vsd
+ Unidirectional
- Counterdirectional
apd = 1–2 (bd + fad) Width of cut
apd Width of cut
in mm
aed Dressing infeed in µm
bd Effective width of the dressing tool in mm
fad Dressing infeed per revolution in mm/U
vfad Axial feed rate in mm/min
vr
Dressing roller circumferential speed in m/s
vsd Grinding wheel circumferential speed in m/s
rp
in mm
Profile radius of the form roller 13
We have what you need –
Form Types
Form dressing rollers
Since the introduction of CNC-controlled dressing processes, a large number of diamond form dressing rollers have entered the market,
making it difficult or impossible to get oriented in the market. With our form dressing roller standard, we strive to reduce the number of
different types to a reasonable size to enable efficient storage and inexpensive manufacturing of the tools. In this manner, we contribute to the
economical optimization of our customers‘ grinding processes.
Form Type 01
Form Type 02
Form roller
U75B
Form Type 03
D B T LH
150 20
The actual reference
52
dimension is
125
15
15
specified in the
100
40
test report.
75
10
10
01 01
01
Form type
01 02 02
02
04
03
02 03 03
03
0404
Variant
R
m
T1B1
min.
NZ
0.3
3
40°
R+1
6
0.003
NS
0.5
3
40°
R+1
6
0.005
IZ
0.3
1
30°
R+1
2
0.01
0.01
IS0.5 1.5 40° R+1 3
(0.003)
SM
0.5
1
30°
4
2
0.02
Other form types or dimensions available on request
Sample order:
WENDT
Form Type D
Variant
U75B02100 NZ
14
Form Type 04
Methods of Application
Different types of form dressing rollers are needed depending on desired grinding wheel profile..
––– First profiling operation
….. Second profiling operation
15
Request, creation of an offer
To allow us to create the technically and
economically optimal offer, we request you
to provide detailed information on the
dressing task and operating conditions of
the desired dressing tool on our data sheet
for requesting an offer. We can also create
an offer based on existing tool or workpiece
diagrams.
Prices
The prices of our dressing tools are based
primarily on the following criteria:
• Precision requirements
• Design variant
• Diamond quality
• Diamond content
• Amount of engineering and manufacturing
work required
• Total scope of delivery
First order
You only need the offer number to place the
order. If there should be any changes, then a
current drawing will also be needed.
Repeat/follow-up order
You only need the article number to place an
order.
3M Abrasive Systems Division
Wendt GmbH
Fritz-Wendt-Str. 1
40670 Meerbusch
Tel.: +49 2159 671-0
Fax: +49 2159 80-624
[email protected]
www.winterthurtechnology.com
Scope of delivery of a diamond tool
•
Test report in the form of a detailed
manufacturing drawing
• Test specimen for profiles manufactured
using the reverse plating method
• Secure packaging in a wooden box placed
inside a larger box
• Free advice and consulting
Warranty claims for defects that can only be
detected during use due to the type of tool
can be recognized up to 12 months after
delivery. To fulfill our warranty obligations,
we will rework or remanufacture the tool, or
we will deduct a proportional amount of the
price based on the value of the products and
services provided.
Lifespan
The life expectancy of our dressing rollers
can vary greatly depending on the variant
selected, the application, and the working
conditions so that we can only provide
figures based on experience:
Reworking
We may be able to rework our dressing
rollers depending on the type of profile and
amount of wear. Our form dressing rollers
with PCD inserts in particular can be
reworked several times. At first, the
geometric condition of the diamond profile is
determined for use as a basis for creating an
offer (except for the diamond form dressing
rollers mentioned above).
Grinding of workpieces with a normal level of
complexity in terms of the profiles and
tolerances as well as average mean surface
qualities: 50,000 – 200,000 dressing
operations.
Grinding of workpieces with fine profiles, low
tolerances, and high surface qualities: 5,000
– 50,000 dressing operations.
Warranty
Our warranty covers the true-to-size and
professional manufacturing of the dressing
tool. All information specified in requests and
orders will be considered when evaluating
any warranty claims. If a lack of information
has led to a suboptimal design, then the
warranty is limited. If no special agreements
were made, then warranty claims can be
recognized up to 6 months after delivery
provided that the tool is new or as good as
new at this time.
The cost of this test will be charged when
the offer is sent even if the test indicates that
reworking is not recommended. The cost of
the test not included in the offering price for
reworking and must be paid for separately. If
you just want us to make a visual inspection
without conducting a detailed test, then we
can do this free of charge as a service, but
our recommendation in this case is nonbinding. Creation of a binding offer for
reworking always requires a detailed test to
be conducted.
Vertriebsniederlassung
Winterthur Technology GmbH
Hundsschleestraße 10
72766 Reutlingen
Tel.: + 49 7121 9324-0
www.winterthurtechnology.com
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We offer more than good products – Sales and Service